Seamless tin plated copper butt connectors with translucent, adhesive lined polyoefin heat shrink tubing. Continuous operating temperature of 61-221 degree F. To ensure waterproof connections: Strip both wire ends 5/16" then insert into the barrel end of the butt connector. Crimp both ends of the barrel butt connector with the wires inside. Apply heat directly to the tubing of the butt connector until the tubing shrinks to a form fit at the wires. Use a heat device of at least 1000 degrees F.